Commit 8cba3234 authored by Sean Nyekjaer's avatar Sean Nyekjaer Committed by Miquel Raynal
Browse files

mtd: rawnand: protect access to rawnand devices while in suspend 



Prevent rawnand access while in a suspended state.

Commit 013e6292 ("mtd: rawnand: Simplify the locking") allows the
rawnand layer to return errors rather than waiting in a blocking wait.

Tested on a iMX6ULL.

Fixes: 013e6292 ("mtd: rawnand: Simplify the locking")
Signed-off-by: default avatarSean Nyekjaer <sean@geanix.com>
Reviewed-by: default avatarBoris Brezillon <boris.brezillon@collabora.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarMiquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20220208085213.1838273-1-sean@geanix.com
parent d430e4ac

drivers/mtd/nand/raw/nand_base.c

+20 −24
Original line number Diff line number Diff line
@@ -338,16 +338,19 @@ static int nand_isbad_bbm(struct nand_chip *chip, loff_t ofs) 
 *

 * Return: -EBUSY if the chip has been suspended, 0 otherwise

 */

static int nand_get_device(struct nand_chip *chip)

static void nand_get_device(struct nand_chip *chip)

{

	/* Wait until the device is resumed. */

	while (1) {

		mutex_lock(&chip->lock);

	if (chip->suspended) {

		mutex_unlock(&chip->lock);

		return -EBUSY;

	}

		if (!chip->suspended) {

			mutex_lock(&chip->controller->lock);

			return;

		}

		mutex_unlock(&chip->lock);



	return 0;

		wait_event(chip->resume_wq, !chip->suspended);

	}

}



/**
@@ -576,9 +579,7 @@ static int nand_block_markbad_lowlevel(struct nand_chip *chip, loff_t ofs) 
		nand_erase_nand(chip, &einfo, 0);



		/* Write bad block marker to OOB */

		ret = nand_get_device(chip);

		if (ret)

			return ret;

		nand_get_device(chip);



		ret = nand_markbad_bbm(chip, ofs);

		nand_release_device(chip);
@@ -3826,9 +3827,7 @@ static int nand_read_oob(struct mtd_info *mtd, loff_t from, 
	    ops->mode != MTD_OPS_RAW)

		return -ENOTSUPP;



	ret = nand_get_device(chip);

	if (ret)

		return ret;

	nand_get_device(chip);



	if (!ops->datbuf)

		ret = nand_do_read_oob(chip, from, ops);
@@ -4415,13 +4414,11 @@ static int nand_write_oob(struct mtd_info *mtd, loff_t to, 
			  struct mtd_oob_ops *ops)

{

	struct nand_chip *chip = mtd_to_nand(mtd);

	int ret;

	int ret = 0;



	ops->retlen = 0;



	ret = nand_get_device(chip);

	if (ret)

		return ret;

	nand_get_device(chip);



	switch (ops->mode) {

	case MTD_OPS_PLACE_OOB:
@@ -4481,9 +4478,7 @@ int nand_erase_nand(struct nand_chip *chip, struct erase_info *instr, 
		return -EIO;



	/* Grab the lock and see if the device is available */

	ret = nand_get_device(chip);

	if (ret)

		return ret;

	nand_get_device(chip);



	/* Shift to get first page */

	page = (int)(instr->addr >> chip->page_shift);
@@ -4570,7 +4565,7 @@ static void nand_sync(struct mtd_info *mtd) 
	pr_debug("%s: called\n", __func__);



	/* Grab the lock and see if the device is available */

	WARN_ON(nand_get_device(chip));

	nand_get_device(chip);

	/* Release it and go back */

	nand_release_device(chip);

}
@@ -4587,9 +4582,7 @@ static int nand_block_isbad(struct mtd_info *mtd, loff_t offs) 
	int ret;



	/* Select the NAND device */

	ret = nand_get_device(chip);

	if (ret)

		return ret;

	nand_get_device(chip);



	nand_select_target(chip, chipnr);
@@ -4660,6 +4653,8 @@ static void nand_resume(struct mtd_info *mtd) 
			__func__);

	}

	mutex_unlock(&chip->lock);



	wake_up_all(&chip->resume_wq);

}



/**
@@ -5438,6 +5433,7 @@ static int nand_scan_ident(struct nand_chip *chip, unsigned int maxchips, 
	chip->cur_cs = -1;



	mutex_init(&chip->lock);

	init_waitqueue_head(&chip->resume_wq);



	/* Enforce the right timings for reset/detection */

	chip->current_interface_config = nand_get_reset_interface_config();

include/linux/mtd/rawnand.h

+2 −0
Original line number Diff line number Diff line
@@ -1240,6 +1240,7 @@ struct nand_secure_region { 
 * @lock: Lock protecting the suspended field. Also used to serialize accesses

 *        to the NAND device

 * @suspended: Set to 1 when the device is suspended, 0 when it's not

 * @resume_wq: wait queue to sleep if rawnand is in suspended state.

 * @cur_cs: Currently selected target. -1 means no target selected, otherwise we

 *          should always have cur_cs >= 0 && cur_cs < nanddev_ntargets().

 *          NAND Controller drivers should not modify this value, but they're
@@ -1294,6 +1295,7 @@ struct nand_chip { 
	/* Internals */

	struct mutex lock;

	unsigned int suspended : 1;

	wait_queue_head_t resume_wq;

	int cur_cs;

	int read_retries;

	struct nand_secure_region *secure_regions;